 This is Brad here at ANU and I'm with Adam and Ion and Liz from ABC Canberra And we're just chatting about how big space is and how far things are in the scales of things So how big is stuff in our solar system? Thank you, Brad. So a Lot of people don't have a good idea of how just how enormous space is so we know the Sun is big But just how big so what we've done here today is we've shrunken the Sun down because it won't fit in our studio To the size of this yoga ball and we've shrunken all the other planets down by the same amount And what we're going to do is play a little game and try to figure out just how big all the planets in our solar system would be Compared to that Sun right there, right? So the first planet in our solar system is Mercury So, Lizh, would you like to take a look and find out which of balls different sized balls here would be Mercury? I'm in the tennis ball. Oh, no, I think that's too big actually given That's the yoga balls on Sun this tiny little mustard seed would be about the size of Mercury so Mercury is the the planet that's very close to our Sun although if we had to put it in the scale of the Sun We would have to place it outside this building. It's so far away from the Sun It's also a tiny planet which looks like the moons with lots of craters So moving along Venus is our next planet and Venus is covered in clouds really thick clouds And it's really hot hotter than your oven and the atmosphere is full of acid So it's not a nice place to be but Venus it's a bit bigger than Mercury But it's still pretty small especially compared to our Sun. So we'll just put that down in front of Venus there, right? The next planet is Earth, which just opposite to Venus is very habitable It's very beautiful Which is why we all live here and it's also the same size as Venus. So I just put that down here And so moving along to the last of our rocky planets is Mars Mars is the red planet And it's really famous lately because we've got a lot of robots on Mars And we're discovering a lot about the geology But Mars would actually only be about the size of this peppercorn and so it's smaller than Earth and Venus But it's still bigger than Mercury, but still tiny compared to the Sun And it's also tiny compared to the gas giants, which we'll move on to next So the next planet, which is the biggest planet in the solar system is Jupiter Would you like to take a guess as to which among this would be Jupiter? Gas giant It's a gas giant Yeah It's not as big as that so given that's our Sun Jupiter would be something of this size Right so there we go. That's Jupiter. That's the gas giant and that's the largest plant of our solar system So now on to what is the prettiest planet of our solar system is Saturn and Saturn is about this big It's a bit smaller than Jupiter and Saturn's got these beautiful rings that go around it and sat next to Jupiter Its rings are actually bigger than Jupiter, but the planet itself is a little bit smaller Right the next planet is an ice giant which is here Uranus And it's also slightly smaller than Saturn But the interesting thing about here in us is that it goes around the Sun on its side Oh, why is that? That's because long long time ago when it was being formed it probably had a huge collision with another planet Which toppled it and so that's why it goes around the side and that's why it has weird seasons And so moving on now to the final planet in our solar system It's Neptune so Neptune is another ice giant and it's dark blue in color and it's the furthest planet out from the Sun And so we spoke about how far Mercury is away from the Sun before at the scale Mercury's in the car park Well Neptune Neptune would be in the next suburb. It's about two and a half kilometers away at this scale So it's even at this tiny scale. It's still huge distance away. The solar system is enormous So this is the relative scale of our solar system and we know on earth You know, we're pulled down to earth by gravity because of the size of our planet Does does the size that we see here affect how much things weigh on those planets actually does which is why we have this water bottles here So for example, if you take this Standard water bottle and this is it's like a 600 ml water bottle and would weigh about 600 grams on earth Right, so you must have seen those footage or clips of astronauts sort of jumping on the moon Right, that's because they feel really light on the moon So if you had to take this bottle to the moon it would weigh something like this There's nothing in it. Yes, it's really light So it would probably be about one-sixth the weight of the bottle on on on earth Yeah, yeah, so so Why is that? Why does that weigh less? That's because the moon is much smaller So the how much our body would weigh on the planet would depend on how heavy it is and how big it is because the moon is much Smaller and it's got a lot less matter The same thing weighs less on the moon because I say if you've got a gas giant that's the biggest is the is Jupiter Even though it's made of gas. Will it still have a Bigger gravity. Yes, so Jupiter being the biggest planet in our solar system actually has about 300 times as much stuff in it as the earth does so it's huge and if you took our water bottle to Jupiter It would weigh like that much Which is really heavy heavy. So we put it on the scales. We'll see that on the surface It weighs about two and a half times more and So we've given you a bit of an idea today just about how gigantic The scales are in the solar system how much things weigh and how far apart they are and Hope you learned a bit and know a bit more than you did before we started